Controllers are used in a wide variety of systems for controlling various functions in homes, office buildings, or other enclosed spaces. In heating, ventilation, and air conditioning (HVAC) systems, for example, such controllers are often used to monitor and control various environmental conditions such as temperature, humidity, venting, air quality, etc. occurring within an enclosed space. Typically, such controllers include a keypad, display panel, a number of switches, and a printed circuit board, each of which can be assembled together within a controller housing and mounted to a wall, frame, or other suitable support panel.
In some designs, a mounting plate can be provided to facilitate electrical connection of the controller to several wire leads located within the support panel. With respect to some wall-mounted thermostat controllers, for example, a wall mounting plate may be provided to facilitate attachment of the controller to a wall containing several wire leads connected to a furnace, boiler, air-conditioner, heat-pump, humidifier/dehumidifier, air-filter, and/or other HVAC component. Typically, the electrical connection of the controller to the mounting plate is accomplished using a pin-in socket connector adapted to receive several connector pins located on the printed circuit board of the controller. In some thermostat assemblies, for example, the mounting plate may include a terminal block having several socket inlets each adapted to receive a corresponding connector pin extending outwardly from the rear of the controller in order to permit the thermostat to be quickly removed from the mounting plate for servicing or maintenance.
The attachment and subsequent removal of the controller from the mounting plate can present a burden to the installer, particularly in those designs where removal of the controller is not intuitive and/or where a significant amount of force is required to disconnect the two components from each other. Prior to installation, the controller and mounting plate are typically separated from each other to permit the installer to first attach the mounting plate to the panel surface and provide the necessary wiring connections to the terminal block. Once the mounting plate is mounted to the panel surface, installation of the controller typically requires the installer to push and/or rotate the controller into place onto the mounting plate. The controller can then be subsequently removed from the mounting plate should servicing or maintenance of the controller become necessary.
In some designs, the process of attaching and/or removing the controller from the mounting plate can result in buckling or bending of the connector pins, causing damage to the controller. In hinged mounted designs, for example, the rotational forces or moments applied to the connector pins as the controller is rotated into place on the mounting plate can cause them to buckle or deform if the pins are not aligned with the socket inlets. In some cases, the misalignment of the controller relative to the mounting plate can also cause damage to the connector pins as the controller is connected to the mounting plate. For example, in straight-in designs where the controller is attached to the mounting plate in a direction normal to the panel surface, a misalignment of the controller can cause the connector pins to buckle or deform as the two components are brought together.
The static interconnect friction of the connector pins within the socket inlets can also render removal of the controller from the mounting plate difficult. In those designs employing multiple connector pins, for example, the pulling and/or rotating force required by the installer to overcome the friction of the connector pins within the socket inlets may be significant, making removal of the controller more difficult. In addition, in those hinged-mounted designs where the controller is adapted to be rotated away from the mounting plate during disassembly, the moments applied to the pins when removed from the socket inlets can cause the pins to bend or deform, producing forces on the pins that can lead to failure of the junction between the pin and the printed circuit board. In surface mounted (SMT) designs where the connector pins are attached directly to the surface of the printed circuit board, for example, these pin moments can lead to wear or cracks on the surface mounts supporting the pins. Furthermore, if the pins are bent during removal from the terminal block, they may be more likely to buckle during subsequent attachment of the controller to the mounting plate due to the misalignment of the pins with the terminal block openings.